Do you know which is worse: second hand smoke or air pollution?

Depends on how much: Pollution and how much smoking. If you live in beijing, the answer might be pollution is as bad or worse than a half-pack of cigarettes per day. If you live in the average american city, smoking is much worse if you are smoking more than a cigarette or two per day. Air pollution has different toxins and they may be worse for some people- like hydrogen sulfide and particulate matter.